Plugged into the coast

Updated Wednesday 13th July 2005

How do we balance the environmental protection of the shoreline with a desire for cleaner fuel?

Copyright: OU

Whoever coined the saying “There’s no such thing as a free lunch” might have been unconsciously intending, gently, to warn environmentalists to remember that all change, including renewable energy alternatives, comes with an ecological price-tag. If we want to use cleaner, greener, energy, our coastlines will just have to grin and bear the costs: different costs, and possibly preferable costs, but costs nonetheless.

The problems we’re facing
The introduction to Greenpeace’s wonderful 1987 book Coastline ended with the hope that it was not too late to inspire participation in the fight to save the coastline. Since then we have seen enormous, continuing, activity in the energy sector, bringing continuing costs. In 2003, UK offshore production of oil totalled 87 million tonnes. This involved 372 oil spill reports that the government knows about, with 83 tonnes of oil entering the briny. And 2003 was a good year: the average for 1991-2003 was 267 tonnes spilled, somewhat skewed by two especially bad years which had 1,390 tonnes between them. These spillages are in addition to the 5,190 tonnes of oil ‘discharged with produced water’ – oil which cannot be separated from the water after they have mixed during the drilling process. All this is without mentioning the tanker disasters: The Braer deposited 84,000 tonnes off Shetland in 1993, and the Sea Empress 70,000 tonnes off South West Wales in 1996.

So oil is problematic for our coastline: what about our biggest single non-CO2 producing energy source (ignoring the argument as to whether it really is so clean), nuclear power? The Irish Sea is described as ‘the most radioactive sea in the world’ following many years of emissions and deposits from Sellafield. The Marine Conservation Society draw attention to the effects of Technetium-99 and Caesium-137 on coastal flora and fauna, and the Low Level Radiation Campaign demonstrate significant human health effects in Wales and Ireland. Sellafield is a special case, in that it stores and reprocesses nuclear waste, but with all of Britain’s commercial nuclear stations being on the coast, and considerable uncertainty surrounding their long-term impact, we cannot be sure of a free lunch here either, even if the UK government embarks on a large nuclear expansion with new, supposedly safer technology.

Considering the options
We could, in theory, avoid all environmental impacts on the coastline from energy production, at some time in the future, by obtaining all our supplies from inland. There are several hundred years of coal (which, by the way, can be burnt much more cleanly and efficiently these days) under our inland feet, and in theory solar power could supply much, if not all, of our electricity and heat. If preserving the coastline is a top priority, perhaps we should go down these roads.

But even if we do this, it would be fraught with problems. Concern about climate change almost certainly precludes further use of coal, current photovoltaics are a very long way from providing much of our electricity, solar heating can only do so much in the UK, and anyway 35% of our energy goes on transport, which could, at a big pinch, be powered by coal-fired electricity, but not realistically by solar. So what can the new offshore technologies offer, and what would be the environmental price for the "lunch" they would offer? There are three main options: tidal power, wind power, and wave power.

Copyright: BBC

Coastal energy: the tides
If you want controversy, if you want environmentalists’ mutually-spilt blood on the organic cotton carpet, talk about tidal power, a topic on which I made myself extremely unpopular with large numbers of eco-friends twenty years ago. I suggested (to paraphrase) that as the proposed (eternally proposed) Severn barrage could produce as much electricity as several nuclear power stations, and as the emissions would be nil, after construction, and as the cost per kilowatt hour over its 125-year life (ignoring the crazy financial conventions which make it seem expensive for the first 25 years), would be negligible, I was not so bothered about the dangers to a few birds. Now, I know that was a simplification of the ecological price for that potential lunch, but Friends of the Earth was split down the middle, and I do wonder what the balance of environmentalist opinion would be if, by some chance, the economics of the project were massaged such that it were realistically offered as an option today.

Luckily, there are other ways of harnessing the enormous potential of the tides around Britain, with much less ecological or physical impact on the coastline. Tidal lagoons are enclosed, stand-alone structures which use essentially the same principle as the barrage: allow the tide in, hold it, then release the water through turbines. So, if you put them in an estuary (they can also be offshore), they are argued to be much less damaging than the barrage, as the tide can flow past them and the upstream mudflats are unaffected. Tidal Electric have a proposed scheme in Swansea Bay, and a Friends of the Earth report in 2004 was extremely favourable, emphasizing the advantages of the lagoon over the barrage, especially the fact that, although the lagoon would enclose less water, its much higher capacity factor (the proportion of its potential capacity which it can actually produce) means that its output per year would be greater. It has one large disadvantage, in that it would require a lot more aggregate in its construction: it is far from clear both where this would come from, and what the overall environmental costs would be.

Even more luckily, a third way of harnessing tidal energy offers itself. ‘Tidal stream’ technology is a device placed underwater, offshore – it can be in an estuary or off a coastline – where it extracts energy from the tidal stream passing over it. This can be like a vertical axis wind turbine, as with Blue Energy’s tidal fence devices in the Philippines, or like a conventional horizontal axis turbine, as with the Marine Current Turbines Ltd Seaflow, which has been operating off the coast of Devon for two years. Even more exciting (to this awe-struck observer) is the Engineering Business Group’s Stingray, tested in the Shetlands in 2002 and 2003. Its monster-from-outer-space-like structure sits on the sea bed, holding out large hydroplanes, like horizontal paddles, which oscillate up and down with the tidal flow.

Coastal energy: the wind
Offshore wind power is the most developed of the coastline energy technologies, with several ‘farms’ either up and running, in construction, or planned. AMEC Border Wind demonstrated, in a study in 1998 that we could supply 40% of our electricity from 4800 km. To put it another way: twenty blocks of sea, each 15 km square – given our coastline stretches for nearly 19,000 km, that’s just 0.03% of the UK controlled seabed. In 2003, the DTI published phase one of the new Strategic Environmental Assessment, which concluded that although there are potential problems they are not serious enough to halt development. It has commissioned long-term studies, and imposed strict environmental criteria to be applied in the case of each proposed wind farm.

Two of the most controversial issues for the public are the danger to birds and the visual impact of windfarms. You don’t need to be looking all that closely to notice quite contradictory reports about birds. “Wind farms pose low risk to birds” was the headline from the BBC on 8 June 2005, quoting research in the Royal Society’s journal. “World's biggest wind farm plan 'threatens seabirds’ ” was the headline in the Guardian, on the same day, quoting an RSPB spokesman referring to fears about the Kentish Flats project. The Danish National Environmental Research Institute found that the Tunø Knob offshore wind farm had ‘no significant impact’ and their latest research, using radar at the Nysted wind farm, shows that birds are adept at avoiding the windfarm: they just fly round it!

For excellent background reading, if you’d like to pursue this, start with the Birdlife International report, written for the Council of Europe in September 2003. This, and all substantial reports, emphasise that continuing research is advisable in this area, and also about the underwater ecology.

On the visual impact, too, it is easy to find contradictory evidence. At Porthcawl in South Wales, the Scarweather Sands offshore wind farm is vehemently opposed by ‘SOS Porthcawl’, but Greenpeace’s opinion survey in the area found that of 650 visitors polled, 83% said that it would make no difference to them, while only 4% said the siting of the wind farm would make them less likely to return to Porthcawl and 13% said it would make them more likely to return.

There are other environmental impacts of offshore wind power, both at installation and in operation. A good source for a detailed discussion on this is the report prepared for Greenpeace by the German Windpower Institute. During the construction phase, there will be damage to the benthos (sea bed flora and fauna) which may be serious if disturbed material settles on feeding grounds, to fish, and to mammals (for example through denial of feeding areas and the noise and vibration from pile-driving) which is impossible to quantify exactly. There will also be discharges of (probably small) levels of pollutants from ships and machinery.

During windfarm operations, in addition to the potential problems with birds, there will again be some disturbance of fish and mammals from vibration, as yet unquantified, some pollution from maintenance equipment, and some effect on fish from the electromagnetic effect of the transmission cables, again difficult to quantify. The general consensus is at present that all these impacts are either known to be, or expected to be, not large enough to prevent development.

One ecological species which may be more difficult to convince is human: the fishermen. The government is drafting a new Marine Bill which will share out power over, and access to, the inshore waters. It is suspected by the fishermen of being about to give far too much weight to the wind power interests. Barry Deas, chief executive of the National Federation of Fishermen's Organisations, was quoted in The Guardian as calling the dispute "a turf war". Since they are also in an uneasy stand-off with the sea-anglers and the dredging companies, we can perhaps assume that the government already knows not to look for free lunches on the coastline.

Copyright: BBC

Coastal energy: the waves
Wave power, using offshore devices (there are onshore ones, but their total output would be small) could, in practical terms, give us about 14% of our electricity. Just as with tidal power, a wide range of weird and wonderful technology has been developed, like the Edinburgh Duck, the Pelamis‘ Seasnake, the Osprey and the Swedish Floating Wave Power Vessel.

The Osprey sits on a large base on the sea bed, and therefore shares some of the wind turbine’s impacts on it, but the other three, and most wave power technology, is either free-floating or simply tethered to the sea bed. It has been suggested that marine life might even benefit from wave power plants by, for example, providing artificial reef conditions underwater and new ‘hauling out space’ for seals. But negative impacts could include changes to food supplies, and changed erosion patterns, caused by reduction in wave energy levels, and – as with wind – disturbance during maintenance and electromagnetic interference from cables. Again, the consensus is that the overall impacts will not be great enough to justify preventing development.

To try to conclude
Oil, gas, nuclear and coal all have some enormous advantages: they are here; we know (more or less) how much of them we can have in the future, and at (more or less) what price; we know, (more or less) what environmental damage they cause, and, (more or less), how this can be avoided or cleaned up.

Tidal, wind and wave power, on the other hand, are not here yet in any quantity; we do not yet know how much of them we can have, or at what price; we think that their environmental impacts are usually tolerable, but we have said that about other technology in the past. We know that they cause ecological damage to the shore or to offshore waters, but we have decided to press on. We hope the damage will not be serious, relative to the large amounts of energy they might offer at some time in the future, and we know that by going ahead we are avoiding other problems associated with conventional energy, especially climate change.

The government has said that it will act to monitor and minimize the impact of wind, tidal and wave power: perhaps we should check occasionally with the Marine Conservation Society whether they agree that the new energy lunch being consumed by the coastline is as near free as we can make it?

Further Reading
For readers who might like to read further about renewable energy, I can (genuinely without obvious bias) strongly recommend two of the textbooks of the OU course on which I teach: Energy Systems and Sustainability, power for a sustainable future, G. Boyle et al eds, OUP & OU [ISBN 0199261792], and Renewable Energy, power for a sustainable future, G. Boyle ed, OUP & OU [ISBN 0199261784].

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As the world responds to climate change, we explore whether sustainable energy can satisfy our need for endless economic growth, without radical changes in the way we live. This album examines power sources which provide cleaner alternatives to fossil fuels, such as wind power, biomass, hydro power, wave and tidal power, solar and geothermal power. The nine video tracks introduce the different approaches adopted in Britain and across Europe, the challenges faced and the projects of the future. This material forms part of S278, Earth's physical resources: origin, use and environmental impact.